Syrian troops are reportedly arresting people at their homes in dawn raids in the central city of Hama, following huge anti-government protests on Friday.
Security forces are believed to have detained more than 20 people, according to the Syrian Observatory for Human Rights.
A Syrian blogger in the city told Channel 4 News that “at least 20 badly beaten people (have been taken to) Horani Hospital. Many residents are blocking the hospital to stop the troops from coming to finish them off”.
On Friday, Hama became the setting of possibly the biggest demonstrations yet against the rule of President Bashar al-Assad.
The city decended into chaos, local residents said, after troops started firing on protesters who had set tyres on fire and blocked roads to delay their movement.
The local governor, Ahmad Khaled Abdel Aziz, was allegedly fired by Assad for failing to suppress the protests.
Hama was the scene of a Muslim Brotherhood uprising against Mr Assad’s father, Hafez, in 1982, which the army crushed, killing at least 10,000 people.
And there are fears of a similar tragedy after tanks were seen surrounding the city. Some are believed to have peeled off in the direction of villages in the north.
In the capital, Damascus, two protesters were reportedly shot dead on Sunday, and unverified video footage of running battles between secuity forces and demonstrators in Homs appears to one protester shot dead.
The young man has been named by Human Rights Watch as activist and blogger Diyya al-Najjar. Reports emerging out of the country say his body was taken to al-Barr hospital, where a doctors said he died from a bullet to the head.
Warning: this footage contains upsetting material
A separate video, posted on YouTube on Sunday and also impossible to independently verify, appears to show a man in Homs being shot dead by a gunman who spots him filming.
At the start of the video, he says: “The armed services are shooting at my countrymen for no reason on 1 July, 2011. There is no protest or anything.”
He focuses his camera, thought to be a mobile phone, on an armed man below the balcony from which he is filming. The gunman sees him filming and shoots in his direction. The cameraman appears to then fall to the ground, moans, with people behing him on the balcony screaming.
Warning: this footage contains upsetting material
Activists say more than 1,350 civilians and 350 security personnel have been killed across Syria since protests began in mid-March.
The uprising shows no sign of letting up, despite a deadly government crackdown that has brought international condemnation and sanctions.
President Assad is facing the most serious challenge to his family’s four-decade rule in Syria.
His administration has blamed a “small faction” of “saboteurs” of exploiting popular grievances.